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Recently, I was trying to get a laptop (that had no ethernet port) connected to an ethernet device. The device communicates via HTTP, and the laptop had Windows OS.

The device manufacturer's tech support suggested getting an off-the-shelf:

  • USB-to-ethernet adapter
  • HDMI-to-ethernet adapter

I have heard of using ethernet cable as HDMI extension cables, but I have never heard of an HDMI-to-ethernet adapter. My question was "does this actually exist?"

My questions are:

  • Can one do network communications through a computer's HDMI port?
  • If yes, does the HDMI port require certain specs?

Research

Quora: Can I use HDMI with an ethernet cable to share internet connection between two laptops?

Hdmi ports on desktops and laptops only send video and audio signals they cannot send data packets so you cannot share your internet connection.

What is Hdmi with Ethernet? How does it work?

Ethernet-enabled HDMI cables can then carry data transmissions from a main source to other IP-based home entertainment devices.

Only devices that feature HDMI Ethernet Channel functionality are able to take advantage of this new feature.

HDMI Cable Types

High Speed HDMI Cable with Ethernet - This cable type offers the same performance (1080p and greater resolutions) as the High Speed HDMI Cable, plus an additional, dedicated data channel, known as the HDMI Ethernet Channel (HEC), for device networking. HEC functionality is only available if both the source and sink devices are equipped with HEC functionality. HEC connected devices that include this feature can send and receive data via 100 Mb/sec Ethernet, making them instantly ready for any IP-based application.

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    \$\begingroup\$ Exists in the HDMI specification but rarely used. Best guess is “no” unless otherwise stated. \$\endgroup\$
    – winny
    Nov 2, 2021 at 18:47
  • \$\begingroup\$ Which laptop would that be? We can't possibly give an answer with the info given. \$\endgroup\$
    – Justme
    Nov 2, 2021 at 19:24
  • \$\begingroup\$ I was more trying to be agnostic from the laptop @Justme, keeping the question general/focused on HDMI as opposed to a specific computer model number \$\endgroup\$ Nov 2, 2021 at 21:15
  • \$\begingroup\$ I’m Question is generic involving standards. Answers given provide good technoca; information liable to be of ongoing use. Closed and then reopened. \$\endgroup\$
    – Russell McMahon
    Nov 5, 2021 at 10:42

1 Answer 1

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The USB Ethernet option is your best bet. Well supported, stable drivers, no-brainer plug in and play, and capable of exploiting a good chunk of a Gbit Ethernet link even with only USB2 high speed. Go buy one and be happy.

Meanwhile, a bit of a screed about HDMI, and how HEC is damage that the rest of the world routed around.

The Ethernet-over-HDMI function is called HEC or HEAC (HDMI Ethernet + Audio Channel.) To my knowledge, no HDMI-out laptops support HEC. You'll only find it on selected consumer electronics like TVs, Blu-Ray players, sound bars and the like. Simple bridge or dongle? Forget it Jake, it's HDMI Town.

Why is that? As a networking connection, HEC is very limited and very boxed-in. It's only 100Mbit/s. It's also not directly compatible with 10/100Base-TX Ethernet, because it uses a hybrid duplexer that combines both Ethernet pairs, Audio Return Channel (ARC) and Hot Plug Detect all onto just two wires (ARC and HPD).

Thus, an HDMI-HEC device is electrically incompatible with anything else but another HDMI-HEC device. To connect HEC to Ethernet, you'll need something like a Blu-Ray player that has both the HEC duplexer and bridge IC, and an Ethernet switch.

HEC also requires special care in selecting a cable: has to be HDMI 1.4/1.4a or later. Not a big deal in the HDMI2.x era, but an old or very cheap cable might not work.

As it is, HEC never really took off with TVs, which started out using wireless or RJ45 connections instead (even going back to the mid-late 2000s when smart TVs first emerged on the market) and stuck with them.

HEC is a solution that arrived too late to market, encumbered by its A/V-centric HDMI mission, answering a question no one was asking. The juice just isn’t worth the squeeze.

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  • \$\begingroup\$ HDMI Ethernet Channel is full duplex though. \$\endgroup\$
    – Justme
    Nov 2, 2021 at 19:28
  • \$\begingroup\$ Nope. It has one pair, half-duplex (pins 14 and 19, with 17 for shield.) More here: summitech.com/2017/01/22/… \$\endgroup\$ Nov 2, 2021 at 19:43
  • \$\begingroup\$ Nope. It has one pair. Full-duplex. hdmi.org/download/… \$\endgroup\$
    – Justme
    Nov 2, 2021 at 19:53
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    \$\begingroup\$ Ahhh, mystical snake oil. Extremely useful, but impossible to get. \$\endgroup\$
    – rdtsc
    Nov 2, 2021 at 19:55
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    \$\begingroup\$ How is that worse? Gigabit Ethernet natively uses a hybrid too for full duplex and it works fine. \$\endgroup\$
    – Justme
    Nov 2, 2021 at 21:00

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